FIG. 37 is a sectional view of a pneumatic tire 01. A carcass ply 03 having two axially opposite annular beads 02 bulges laterally. Circumferential belts 04 overlie the carcass ply 03, a rubber tread 05 circumferentially surrounds the belts 04, and the rubber tread 05 is coupled to the annular beads 02 by side walls 06. Thus, the pneumatic tire 01 has a substantially toroidal shape. An inner liner 07 is placed on the inner surface of the carcass ply 03 of the pneumatic tire 01. A length between the beads 02 along the inner surface of the inner liner 07 is designated as section width Ws. Thus, the inner liner 07 has a width substantially equal to the section width Ws.
Referring to FIG. 38, in a process of manufacturing the inner liner 07, an extruder 010 having a roller head 011 sends out a continuous strip 08 of a width W substantially equal to the section width Ws continuously. The continuous strip 08 is cut into inner liner blanks 07 of a predetermined length P each for one tire. As shown in FIG. 38, the inner liner blank 07 is wound around a forming drum 012, the opposite end edges of the inner liner blank 07 are joined together, a carcass ply is wound around the inner liner blank 07, and an assembly of the inner layer blank 07 and the carcass play is subjected to a forming process. A calender may be used instead of the extruder 010 for forming the continuous strip 08. A continuous strip formed by a calender has a width W substantially equal to the section width Ws.
Since the continuous strip has the width W substantially equal to the section width S2, the production of the continuous strip needs a large extruder or a calender, and a large plant. The extruder or the calendar has a production capacity far greater than that of the forming machine. Therefore, if the large extruder having a high production capacity is combined directly with the forming machine provided with a forming drum to form a production line, the production line is unable to operate at a high line speed, i.e., a production speed, due to the difference in production capacity between the extruder or the calender, and the forming machine and, consequently, the temperature of the continuous strip of rubber drops and the quality of the surface of the continuous strip is deteriorated.
Actually, a continuous strip formed by the extruder or the like is wound in rolls, and the rolls are stored. When the roll is used for forming an inner liner, the continuous strip is unwound from the roll and cut into cut strips, and the cut strips are fed one by one to the forming machine. Thus, spaces are necessary for storing and transporting the rolls of the continuous strip, the scale of the plant increases accordingly, and the equipment cost of the plant is high.
Conventional methods of forming carcass plies and belts include the following processes. A continuous strip formed by coating a plurality of cords with rubber is wound in a large roll. The continuous strip is unwound from the large roll, the continuous strip is extended on a conveyor with its leading edge placed at a predetermined position on the conveyor, the continuous strip is cut in a cut strip of a predetermined length by a ply cutting machine, the cut strip is turned through an angle of 90°, the conveyor is driven to move the cut strip by a predetermined distance, and a side edge part of the cut strip is joined to a side edge part of the preceding cut strip. These processes are repeated to form a continuous carcass ply continuous strip or a belt continuous strip, and the carcass ply continuous strip or the belt continuous strip is wound in rolls. The carcass ply continuous strip or the belt continuous strip unwound from the roll is cut into cut strips of a predetermined length corresponding to the size of a tire, and the cut strips obtained by cutting the carcass ply continuous strip or the belt continuous strip are processed by forming machines to form carcass plies or belts. The conventional methods need those machines and many processes, require inefficient work, and need a large-scale apparatus, a large floor space and a large plant and equipment investment.